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Tall, pot-bellied feathered dinosaur with enormous hand claws, in side view
Life restoration of Therizinosaurus cheloniformis, with claws and arms based on the holotype PIN 551-483 and specimens MPC-D 100/15-17.Image credit: PaleoNeolitic, CC BY 4.0, via Wikimedia CommonsCC BY 4.0Source (opens in a new tab)

Therizinosaurus cheloniformis

Pronounced THER-ih-ZIN-oh-SORE-us keh-LOH-nih-FOR-mis

Therizinosauria · Therizinosauridae

A giant therizinosaur from the Late Cretaceous Nemegt Formation of Mongolia, known mainly from its arms and huge hand claws. A theropod that most likely ate plants.

  • Feathered
  • Bipedal
  • Giant
  • Giant claws
  • Unusual anatomy
Compare
Period
Cretaceous· Maastrichtian
Diet
Herbivore
Length
9–10 m
Mass
5,000 kg
Location
Mongolia, Ömnögovi Province

Quick answers

How big was Therizinosaurus cheloniformis?
Therizinosaurus cheloniformis was about 9–10 m long. It stood about 2.8–3.5 m tall at the hips. It weighed about 5 t. (Paul 2010; Paul 2016)
When did Therizinosaurus cheloniformis live?
Therizinosaurus cheloniformis lived during the Late Cretaceous, about 72.1–66 million years ago. (Cohen et al. 2023; Zanno 2010)
Where have Therizinosaurus cheloniformis fossils been found?
Fossils of Therizinosaurus cheloniformis have been found in Nemegt Formation (Ömnögovi Province) and Mongolia. (Maleev 1954; Zanno 2010)
What did Therizinosaurus cheloniformis eat?
Therizinosaurus cheloniformis was a herbivore. (Maleev 1954; Zanno 2010)
Who named Therizinosaurus cheloniformis, and when?
Therizinosaurus cheloniformis was described by Evgeny Maleev in 1954. (Maleev 1954; Zanno 2010)
Was Therizinosaurus cheloniformis in Jurassic Park?
Yes. Therizinosaurus cheloniformis appears in Jurassic World Dominion (2022). A feathered, near-blind giant with scythe-like claws that impales the Giganotosaurus at the climax of Dominion. It was a plant eater: the giant claws were probably for pulling down branches, not for fighting predators. (Wikipedia: Dinosaurs in Jurassic Park 2026; Lautenschlager 2014)

On this page

Period
Cretaceous72.1–66 Ma
Diet
Herbivore
Length
9–10 m
Mass
5 t
Location
Mongolia
Classification
Therizinosauria · Therizinosauridae
Described
1954, Evgeny Maleev

Overview

Therizinosaurus cheloniformis lived in what is now the Gobi Desert of Mongolia in the Late Cretaceous. Evgeny Maleev named it in 1954 from enormous flat claws found by a Soviet-Mongolian expedition in the Nemegt Formation, and he took them for the remains of a giant turtle-like reptile.

Later finds of arms and hind limbs showed it was a theropod, part of the strange group Therizinosauria (Zanno 2010). Its relatives had small heads, long necks, broad bellies and four-toed feet. Therizinosaurus itself is known only from limbs and a few other bones, so its full body is reconstructed from those relatives.

Its hand claws are among the longest of any known animal. Despite belonging to the meat-eating theropods, therizinosaurs show leaf-shaped teeth, beaks and wide guts, and Zanno and Makovicky (2011) treat the group as herbivorous. The claws were probably used for pulling down branches, display or defence rather than hunting.

Name meaning

From Greek therizo ("to reap") and sauros ("lizard"): "reaping lizard", for the scythe-like claws; cheloniformis means "turtle-shaped", from Maleev's first interpretation (Maleev 1954).

Biology & evidence

What scientists think about how this animal lived, and how strong the evidence for each idea is.

Feeding

  • Therizinosaurus was mainly a plant-eater.

    Evidence level: Moderate evidence

    No skull of Therizinosaurus is known, but its relatives have plant-eater teeth, beaks and wide bellies. It is inferred from them, which is why the evidence is moderate rather than strong.

    Evidence for / against · 1
    Evidence for

    • Comparative anatomy · Therizinosaur leaf-shaped teeth and beaks

      Relatives of Therizinosaurus with skulls show leaf-shaped cheek teeth and a toothless beak at the front of the jaws, as in plant-eaters.

Feathers

  • Therizinosaurus probably had some feathers.

    Evidence level: Hypothesis

    No skin or feathers are known from Therizinosaurus. Smaller relatives had filament feathers, but very large animals may have lost much of their coat, so this is an inference.

    Evidence for / against · 1
    Evidence for

    • Feather impression · Filamentous feathers on Beipiaosaurus

      A smaller Early Cretaceous therizinosaur from China preserved with feather-like filaments.

Biomechanics

  • The giant claws of Therizinosaurus were used to pull branches, not to dig or kill.

    Evidence level: Hypothesis

    Computer models show the long, gently curved claws would break under digging loads but could hook and pull branches. Display and defence are also possible.

    Evidence for / against · 1
    Evidence for

    • Biomechanical model · Therizinosaur claw finite-element models

      Models of therizinosaur claws find the long, straight claws of Therizinosaurus poorly suited to digging and better for pulling vegetation or display.

      Specimen: PIN 551-483

Size

Length
9–10 m

(32.8 ft)

Height
3.1 mpublished range 2.8–3.5 m

(10.2 ft)

Based on IGM 100/45 (partial hindlimb)

Mass
5,000 kg
Therizinosaurus cheloniformis was about 10 m (32.8 ft) long, roughly 5.6 times the height of a 1.8 m adult human.

Timeline

Lived from about 72.1 to 66 million years ago (Ma), within the Mesozoic era (252–66 Ma).

Periods: Maastrichtian (72.1–66 Ma), Late Cretaceous (100.5–66 Ma)

Ages are the ICS 2023/09 bounds of the Maastrichtian, the stage(s) the fossils are assigned to; they bracket the record and are not dated first/last appearances. The Nemegt Formation is usually considered early Maastrichtian, but it has no radiometric dates; some authors allow a late Campanian age.

Location

Formations

Map data: Natural Earth (public domain). Modern positions, not where the continents were then.

These are the places where fossils have been found, not the full area where the animal lived.

Ecosystem

Nemegt Formation scene with Therizinosaurus, the pachycephalosaur Prenocephale and the dromaeosaurid Adasaurus.Image credit: ABelov2014, CC BY 3.0, via Wikimedia CommonsCC BY 3.0Source (opens in a new tab)

Lived in: Nemegt

72–68 million years ago · river system, floodplain, forest, swamp / wetland

Wetter than the Djadokhta dunes before it: braided rivers, channels and floodplain forests in the Late Cretaceous Gobi, supporting large herbivores and the tyrannosaurid Tarbosaurus.

Same ecosystem

Tarbosaurus bataar

Cretaceous· MaastrichtianCarnivore

Same ecosystem

Deinocheirus mirificus

Cretaceous· MaastrichtianOmnivore

Same ecosystem

Gallimimus bullatus

Cretaceous· MaastrichtianOmnivore

Classification

  1. cladeDinosauria
  2. cladeSaurischia
  3. cladeTheropoda
  4. cladeCoelurosauria
  5. cladeManiraptora
  6. cladeTherizinosauria
  7. familyTherizinosauridae
  8. genusTherizinosaurus
  9. speciesTherizinosaurus cheloniformis

Taxonomic status: Valid

Fossil record

Forelimbs of Therizinosaurus cheloniformis MPC-D 100/15 with their giant claws.Image credit: Pablo Rodríguez, CC BY-SA 2.0, via Wikimedia Commons (unmodified except resizing)CC BY-SA 2.0 (unmodified)Source (opens in a new tab)
Specimens
Catalog numberStatusInstitutionFound
PIN 551-483HolotypeBorissiak Paleontological Institute, Russian Academy of Sciences (PIN)1948
MPC-D 100/15Referred specimenInstitute of Paleontology, Mongolian Academy of Sciences (MPC)—

What has been found

Holotype: PIN 551-483

  • Preserved
  • Partial
  • Reconstructed
  • Unknown / not recorded

Holotype: PIN 551-483

Region by region (table)
Skeleton regions of Holotype: PIN 551-483
RegionState
SkullUnknown / not recorded
MandibleUnknown / not recorded
TeethUnknown / not recorded
Cervical vertebraeUnknown / not recorded
Dorsal vertebraeUnknown / not recorded
SacrumUnknown / not recorded
Caudal vertebraeUnknown / not recorded
RibsPartial · Rib fragment.
GastraliaUnknown / not recorded
Scapula / shoulder girdleUnknown / not recorded
HumerusUnknown / not recorded
Forearm (radius / ulna)Unknown / not recorded
Hand (manus)Partial · Three ungual claws.
PelvisUnknown / not recorded
FemurUnknown / not recorded
Tibia / fibulaUnknown / not recorded
Foot (pes)Unknown / not recorded

Referred specimen: MPC-D 100/15

Region by region (table)
Skeleton regions of Referred specimen: MPC-D 100/15
RegionState
SkullUnknown / not recorded
MandibleUnknown / not recorded
TeethUnknown / not recorded
Cervical vertebraeUnknown / not recorded
Dorsal vertebraeUnknown / not recorded
SacrumUnknown / not recorded
Caudal vertebraeUnknown / not recorded
RibsUnknown / not recorded
GastraliaUnknown / not recorded
Scapula / shoulder girdlePreserved
HumerusPreserved
Forearm (radius / ulna)Preserved
Hand (manus)Partial
PelvisUnknown / not recorded
FemurUnknown / not recorded
Tibia / fibulaUnknown / not recorded
Foot (pes)Unknown / not recorded
Labelled diagram of the Therizinosaurus arm MPC-D 100/15 beside a human for scale, after Barsbold (1976).Image credit: PaleoNeolitic, CC BY 4.0, via Wikimedia CommonsCC BY 4.0Source (opens in a new tab)

All specimens

Discovery

Year described
1954
Described by
Evgeny Maleev
Type specimen
PIN 551-483

Discovery timeline

  1. 1948 · First material found

    Soviet-Mongolian expedition collects giant claws

    Huge flat claws are collected in the Nemegt Basin.

  2. 1954 · Formally described

    Maleev names Therizinosaurus as a turtle-like reptile

    Maleev names the animal and interprets it as a giant turtle-like reptile.

    People: Evgeny Maleev

  3. 1976 · Major study

    Barsbold describes Therizinosaurus arms

    New arm material shows Therizinosaurus was a dinosaur with enormous hands.

    People: Rinchen Barsbold

In Jurassic Park & Jurassic World

Films

  • Jurassic World Dominion (2022)

On screen

A feathered, near-blind giant with scythe-like claws that impales the Giganotosaurus at the climax of Dominion.

Film vs fossils

  • It was a plant eater: the giant claws were probably for pulling down branches, not for fighting predators.
  • Feathers are plausible: a close relative preserves feather-like filaments.

Film titles are used for identification only. DinoDex is not affiliated with or endorsed by the Jurassic Park / Jurassic World franchise. All dinosaurs seen in the films

Sources

  1. (2026). Wikipedia: Dinosaurs in Jurassic Park. Wikipedia. https://en.wikipedia.org/wiki/Dinosaurs_in_Jurassic_Park (opens in a new tab)
  2. Cohen, K. M., Harper, D. A. T., Gibbard, P. L. & Car, N. (2023). International Chronostratigraphic Chart (v2023/09). International Commission on Stratigraphy. https://stratigraphy.org/ICSchart/ChronostratChart2023-09.pdf (opens in a new tab)
  3. Lautenschlager, S. (2014). Morphological and functional diversity in therizinosaur claws and the implications for theropod claw evolution. Proceedings of the Royal Society B 281: 20140497. doi:10.1098/rspb.2014.0497 (opens in a new tab)
  4. Maleev, E. A. (1954). Novyy cherepakhoobraznyy yashcher v Mongolii [New turtle-like reptile in Mongolia]. Priroda 1954(3): 106-108.
  5. Paul, G. S. (2010). The Princeton Field Guide to Dinosaurs. Princeton University Press.
  6. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
  7. Xu, X., Tang, Z. & Wang, X. (1999). A therizinosauroid dinosaur with integumentary structures from China. Nature 399: 350-354. doi:10.1038/20670 (opens in a new tab)
  8. Zanno, L. E. (2010). A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora). Journal of Systematic Palaeontology 8(4): 503-543. doi:10.1080/14772011003644595 (opens in a new tab)
  9. Zanno, L. E. & Makovicky, P. J. (2011). Herbivorous ecomorphology and specialization patterns in theropod dinosaur evolution. Proceedings of the National Academy of Sciences 108(1): 232-237. doi:10.1073/pnas.1011924108 (opens in a new tab)